An augmented reality (AR) technology is known by which display information is superimposedly displayed over a part of an image that has been captured by a camera (image-capturing unit) provided in a terminal device. A digital content that is an example of the display information displayed using the AR technology is called an AR content or the like. By displaying the AR content whose orientation and size has been adjusted in the captured image that is displayed on the screen, the terminal device may display the AR content as if the AR content exists in a space captured by the camera.
To the AR content, a positional relationship with a reference object (for example, an AR marker or the like) is defined. A positional relationship between the camera and the AR content is calculated based on a positional relationship between the reference object and the camera, and a positional relationship between the AR content and the reference object. An image of the AR content that is to be displayed on the screen is generated by projecting the AR content in a direction that corresponds to the positional relationship between the camera and the AR content.
The AR content such as a superimposed image, which is displayed based on the AR marker recognized by the terminal device, includes a content that is registered by the operation of an operator or the like, in addition to a content that is registered by the operation of an administrator in advance. Due to registration operations, the users such as the administrator and the operator may set the AR content at a relative position from the AR marker. This technique is disclosed in Japanese Laid-open Patent Publication No. 2007-293895.